The present invention relates to an industrial or medical radiation detector and a radiation imaging device equipped with the same. More specifically, the present invention relates to technology for improving detection characteristics and production efficiency for radiation detectors.
High-sensitivity radiation detectors are developed for industrial and medical radiation detectors. An insulative body such as aluminum oxide, silicon carbide, or the like is used as a support substrate of the radiation detector. A CdTe, CdZnTe (cadmium lead telluride) crystal is used as a semiconductor sensitivity film. Also, accumulation/reading elements are arranged to correspond to the two-dimensional array of detector elements for accumulating and reading carriers (electrons, positive holes) generated by the semiconductor sensitivity film in response to exposure to the radiation being detected. The generated carriers are collected element by element (see Japanese laid-open patent document publication number 2001-242256).
However, this type of conventional technology has the following problems.
When the support substrate is an insulative body, a shared electrode must be included between the support substrate and the semiconductor sensitivity film and a bias voltage must be supplied to the shared electrode. Thus, wiring involving fine processing is required. More specifically, since the shared electrode is thin, wiring to supply the bias voltage from a side surface is difficult. Actual processing may involve cutting away a section of the support substrate to connect the shared electrode or to make an electrical connection via a through-hole. Thus, complexity is added to the manufacturing process. Also, since this shared electrode is thin, the electrical resistance is high, leading to variations in the detector bias voltage and reduction in the sensitivity of the radiation detector.